(a) Field of the Invention
The present invention relates to an adjustable bicycle stem, particularly to an improved structure in which the horizontal tube can be adjusted to an upward or downward position, this improved structure uses a rotatable shuttle-shaped threaded tube to cooperate with a push member for adjusting the angle of the horizontal tube.
(b) Description of the Prior Art
Conventional bicycle stems consist of a horizontal C-shaped connector and a longitudinal C-shaped connector, these connectors are respectively provided for adapting the handle and steering tube of the bicycle. The shape of the stem can either be straight or formed into an inverted L-shaped stem, however, these tubes are integrated into one piece, they do not provide any adjustment for the horizontal tube and the longitudinal tube.